The Bioanalytical/Mass Spectrometry/Proteomic Core (MS/Proteomics Core) provides cost-effective, state of-the-art instrumentation and expertise to investigators in the Vanderbilt Digestive Disease Research Center (VDDRC). This core is among the specialized service cores utilizing the technical personnel and instrument facilities located in the Vanderbilt Mass Spectrometry Research Center (MSRC). This core will be used for identification and quantitation of small molecule metabolites and identification and characterization of proteins. Forty six (46) VDDRC investigators have used the core extensively during the previous five years for digestive disease related projects, such as assistance in developing analytical methods or experimental design, performing analysis of complex protein samples. The core develops standard operating procedures, and maintains quality control (QC) records on particular assays, instrument performance, and maintenance history. Core personnel perform assays for investigators and train students and fellows in the theoretical and practical aspects of MS. The MS Core component is run as an open-access facility in which users generally prepare their samples and operate the instruments if they so desire. Proteomics samples are submitted to the core for analysis by proteomics staff after consultations between the investigator and core staff have determined the most appropriate class of analytical service. Personnel handle all aspects of sample processing, analysis, and data reporting of samples submitted for proteomics analysis. Administrative staff monitors the use of the instrument facilities by investigators and prepare reports on utilization for use by the Administrative Core. The MSRC cores have 18 mass spectrometers available to users, in addition to specialized facilities for 2D-differential gel electrophoresis and gel imaging. The Specific Aims of the Core are to: 1) provide high-quality GC/MS, tandem LC/MS, and MALDI/TOF mass spectrometry services for analysis of small molecule metabolites; 2) provide proteomics services for identification and characterization of individual proteins and more complex tissue-specific proteomes; (3) provide analytical expertise in mass spectrometry for assay development and validation; 4) assist users with data analysis; and 5) provide advanced training in biomedical mass spectrometry and proteomics to students and fellows. The goal of the Core is to enhance investigator abilities to prevent, diagnose or treat human digestive disease-related disorders.